HISTOPATHOLOGICAL APPROACH TO THE DIAGNOSIS OF BENIGN PERIPHERAL NERVE SHEATH TUMORS AT UNCOMMON LOCATION

Abstract

Peripheral nerve sheath tumors are relatively common lesions that exhibit a wide morphological and biological spectrum. In the presence of classical morphological and immunohistochemical features, the histological diagnosis is usually straightforward, but they may represent diagnostic challenges. Schwannoma is a slow growing encapsulated tumor of neuroectodermal derivation that originates from the Schwann cells of the neural sheath. Most commonly presents as cerebellopontine angle mass but extracranial sites are known and needs to be considered in the differential diagnosis. Intraparotid and penile schwannomas are extremely rare. Their diagnosis could be missed on cytology due to cystic changes. Isolated plexiform neurofibroma of the tongue is again a rare tumor. Plexiform pattern recognition is important for the pathologist as these varients might show malignant transformation. Overall Fine needle aspiration cytology though inconclusive at times, help a lot initially to delineate between benign Vs malignant lesions. Moreover its minimally invasive so can be performed easily at the uncommon locations. Histopathology remains the gold standard. Clinicopathological and imaging correlation is must for definite diagnosis and treatment.